Nic Nicolas Borchers Arriagada

University of Tasmania

Nicolás is a PhD Candidate in Medical Sciences at the Menzies Institute for Medical Research from the University of Tasmania. His research interests involve the application of engineering-type tools, economics, and modelling to policy-related environmental and energy problems. During his PhD, he will introduce health impact and economic assessments into the evaluation of the health burden of bushfire smoke in Australia. 


Nicolás comes from Chile where he completed his undergraduate studies as an Industrial Engineer with a Diploma in Environmental Engineering at the Pontificia Universidad Católica de Chile. After working several years as an environmental and sustainability consultant, he completed a Master of Environment at the University of Melbourne in Australia. On his return to Chile in 2014 he worked as an environmental data analyst at the Environmental Enforcement Agency, where he gained better knowledge about environmental regulations and the use of analytics tools for data manipulation and the assessment of environmental compliance. With more than ten years of working experience in areas such as air quality and human health impacts, public policy, public health, environmental regulations and analytics, and decision-support systems, Nicolás looks forward to merging this knowledge into applicable tools and frameworks that will contribute to improve human wellbeing. 

Project Status: Completed 2022
Grant Type: PhD

Why was funding this research important?

Wildfire risk reduction strategies (such as hazard reduction burning) have significant impacts on people with asthma through production of smoke and fine particulate matter (PM2.5).

“People with asthma are amongst the most and first affected with fire smoke episodes. I hope that my research helps raise awareness of the health burden associated with fire smoke, and push for improving the lives of people with asthma at least in the following two ways: 1) Inform people with asthma about the risks of being exposed to fire smoke, whether this comes from prescribed burn activities or bushfires, and 2) Increase awareness of decision makers so that this issue (fire smoke and health) is incorporated in the fire management risk communication process.”

-Nicolas Borchers

During wildfires and interventions such as prescribed burning, a large population might be exposed to very high short-term (ranging from hours to days) concentrations of PM2.5. There is strong evidence these episodes cause increased asthma symptoms and medication use, and increased incidence of hospital admissions for asthma. This is why it is essential that the health and economic costs of bushfires and bushfire management strategies such as prescribed burning explicitly consider the health impacts of smoke. 

What are the researchers doing?

To answer the previous research gaps, Nicolas’s research project (PhD thesis) was carried out with the aim of determining the health burden of bushfire smoke in Australia, by addressing the following research questions:  

  • What is the association between landscape fire smoke-related PM2.5 and hospital emergency department attendances and admissions for asthma, and is this comparable to that from a typical urban PM2.5?  
  • What is the health burden and health costs of bushfire smoke in Australia, and is it similar to other biomass combustion pollution sources like wood heater emissions?  
  • How does the health burden and health costs from prescribed burning smoke compare to that of wildfire smoke?

“Initially, funding from Asthma Australia shifted my focus to have a closer look at the impacts of bushfire smoke on asthma, and not just overall disease. I was surprised to see that impacts of fire smoke PM 2.5 on asthma outcomes are quite relevant, and considerably higher than those of a ‘typical’ PM 2.5 mixture, which include different emissions sources such as mobile, industrial and residential.”

-Nicolas Borchers

What did the researchers find?

The most important findings from Nicolas’s PhD thesis can be summarised as:  

1. Landscape Fire Smoke (LFS)related PM2.5 is positively associated with asthma-related outcomes, and that this association is higher than that for a typical urban PM2.5 mixture. We don’t understand yet how the health effects from LFS-PM2.5 and typical urban PM2.5 compare for other health outcomes, and this is something that should be further explored.  

2. The health burden and costs of bushfire smoke is substantial in the Australian context, particularly during extreme fire years. This was evident from the analysis done for the 2019-20 bushfire season (or “Black Summer bushfires”) where I estimated that 417 premature deaths, 3151 cardiorespiratory hospitalisations and 1305 asthma ED attendances were attributable to bushfire smoke exposure in Queensland, New South Wales, the Australian Capital Territory and Victoria, for the period between 1 October 2019 and 10 February 2020. 

3. The smoke-related health burden and costs from prescribed burns is comparable to that of wildfires. This was revealed from two modelling studies. In WA, historical impacts from prescribed burning smoke – only considering PM exceedances – are higher than those from wildfires. In NSW, although the total smoke-related health cost for wildfires is higher than that for prescribed burning, the cost per hectare burnt is higher for prescribed burning under multiple varying conditions and scenarios.  

This research helped demonstrate the health and resulting economic impacts of landscape fire smoke, particularly for people with asthma. It also demonstrated the human health impacts of current fire management practices like prescribed burning, particularly for people with pre-existing conditions such as asthma.  

“I hope this research helps push for better public health and fire management policies and practices, by highlighting the need for the incorporation of the smoke-related health costs and benefits when evaluating wildfire risk reduction strategies.”

-Nicolas Borchers

This research also highlights that more efforts should be put into the assessment of the effectiveness of interventions to reduce smoke, whether through preventing smoke exposure (e.g. better public health communication, early alert systems, HEPA filters), or better and different fire management practices (e.g. alternatives to prescribed burning such as mechanical thinning, or better planning of times and locations of prescribed burns).

Related Publications

1. Borchers Arriagada, Horsley, Palmer, Morgan, Tham and Johnston 2019, Association between fire smoke fine particulate matter and asthma-related outcomes: Systematic review and meta-analysis, Environmental Research, 179(A), doi:  

2. Borchers Arriagada, Bowman, Palmer and Johnston 2020, Climate Change, Wildfires, Heatwaves and Health Impacts in Australia. In: Akhtar R. (eds) Extreme Weather Events and Human Health, Springer, doi:  

3. Borchers-Arriagada, Palmer, Bowman,  Williamson and Johnston 2020, Health Impacts of Ambient Biomass Smoke in Tasmania, Australia, International Journal of Environmental Research and Public Health 17(9), 3264, access online:  

4. Borchers Arriagada, Palmer, Bowman, Morgan, Jalaludin and Johnston 2020, Unprecedented smoke-related health burden associated with the 2019-20 bushfires in eastern Australia, Medical Journal of Australia, doi: 10.5694/mja2.50545  

5. Borchers Arriagada, Palmer, Bowman and Johnston 2020, Exceedances of national air quality standards for particulate matter in Western Australia: sources and health-related impacts, Medical Journal of Australia, accessed online:  

6. Johnston, Borchers-Arriagada, Morgan, et al 2021, Unprecedented health costs of smoke-related PM2.5 from the 2019–20 Australian megafires., Nat Sustain4, 42–47, accessed online: 

7. Borchers-Arriagada, Bowman, Price et al 2021, Smoke health costs and the calculus for wildfires fuel management: a modelling study, The Lancet Planetary Health, accessed online: